Various tone hole pads for wind instruments have been long known.
The prior constructions have drawbacks. The constructions are not conducive to maintaining a flat sealing surface against a tone hole nor to minimize expansion or shrinkage when exposed to weather changes or stage lights nor to seal around the tone hole seat with a very light touch of the key nor to maintain a uniformity of contact in a poorly designed or bent pad cup.
While the pads of the known art vary greatly in construction they fail to overcome the known problems in maintaining a long lasting sealing effect over a period of time when subjected to adverse conditions.
Considerable information on the problems and technology of the art is found in the following publications:
Understanding the Complicated Process of Making Flute Pads Work, published in the November 1983 Newsletter of the National Flute Association (Vol. IX, no. 1), written by Ross Prestia and published by the National Flute Association Newsletter, c/o Myrna Brown, 805 Laguna Drive, Denton, Texas 76201. PA1 The Complete Guide to the Flute from Acoustics and Construction to Repair and Maintenance, by James Phelan and Mitchell D. Brady, published by Conservatory Publications, Boston, 1980. (Chapter 7 particularly pertains to "Padding, Corks, Felts and Adjustments").
The art heretofore known utilizes partial shims of thin material in the pad holding cup of the key arm to compensate for air leaks between the pad skin surface and the seat of the tone hole. No pad hitherto known is constructed so as to be bendably adjustable for leaks. Pads will pull the cardboard backing of the pad away from the back of the cup if the skin shrinks. Also, shrinking of the skin causes the outer edge of the cushion to be drawn in, causing leakage.
Thick cardboard backing may be used to minimize warping of a pad, as is used in students' flutes, but such constructions cannot be carefully leveled to the tone hole seat. Also, the problem still remains of the skin drawing the outer edge of the cushion away from the edge of the pad cup thus causing leaking. These problems cause the pad surface to no longer be in a flat plane.
As will be apparent from what follows, the warping problems and leakage are eliminated in my invention by recessing the cushion in a backing member and stretching the skin over the cushion with support on coaxial collars so that the cushion is essentially flat despite any shrinking of the skin.